logiguard fork: GPUI xdg-activation keyboard-focus serial fix

Single-commit orphan branch: full zed-industries/zed @ 8c74db0 source tree
with a 3-file patch applied (no upstream history).

Patch (crates/gpui_linux/src/linux/wayland/):
  - serial.rs: add SerialKind::KeyboardEnter
  - client.rs: store wl_keyboard.enter serial; add latest_serial_of()
  - window.rs: activate() uses keyboard-enter serial (Mutter focus gate)

Mutter honors window activation only when the token carries the keyboard-
focus serial from wl_keyboard.enter; GPUI used a stale mouse-press serial.
See docs/tray-window-focus-wayland.md in logiguard.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

crates/image_viewer/Cargo.toml

@@ -0,0 +1,35 @@
+[package]
+name = "image_viewer"
+version = "0.1.0"
+edition.workspace = true
+publish.workspace = true
+license = "GPL-3.0-or-later"
+
+[lints]
+workspace = true
+
+[lib]
+path = "src/image_viewer.rs"
+doctest = false
+
+[features]
+test-support = ["gpui/test-support", "editor/test-support"]
+
+[dependencies]
+anyhow.workspace = true
+db.workspace = true
+editor.workspace = true
+file_icons.workspace = true
+gpui.workspace = true
+language.workspace = true
+log.workspace = true
+project.workspace = true
+serde.workspace = true
+settings.workspace = true
+theme_settings.workspace = true
+ui.workspace = true
+util.workspace = true
+workspace.workspace = true
+
+[dev-dependencies]
+editor = { workspace = true, features = ["test-support"] }